Outboard motor having a water jet impellor unit

ABSTRACT

An outboard motor of the type having a water jet impellor unit, which has an outer shell for clamping rigidly to the transom of a boat and resilient suspension means for supporting the engine and a water propeller on the said shell. The propeller shaft is aligned with the output shaft of the engine and coupled thereto at one end by means of a coupling including a thrust bearing, the other end of the propeller shaft carries the propeller and is carried by a water cooled bearing in the duct of the water jet impellor unit. The engine is cooled by water drawn from the duct of the impellor unit up a sleeve surrounding the propeller shaft, and the water circulating conduit includes a removable filter element for trapping foreign bodies.

United States Patent [19.1

Giacosa OUTBOARD MOTOR HAVING A WATER JET IMPELLOR UNIT [75] Inventor: Dante Giacosa, Turin, Italy [73] Assignee: Sira Societa Industriale Ricer che Automotoristiche, Turin, Italy [22] Filed: May 8, 1973 [21] Appl. No.: 358,435

[30] Foreign Application Priority Data Apr. 30, 174

Primary ExaminerTrygve M. Blix Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT An outboard motor of the type having a water jet impellor unit, which has an outer shell for clamping rigidly to the transom of a boat and resilient suspension means for supporting the engine and a water propeller on the said shell. The propeller shaft is aligned with the output shaft of the engine and coupled thereto at one end by means of a coupling including a thrust bearing, the other end of the propeller shaft carries the propeller and is carried by a water cooled bearing in the duct of the water jet impellor unit. The engine is cooled by water drawn from the duct of the impellor unit up a sleeve surrounding the propeller shaft, and the water circulating conduit includes a removable filter element for trapping foreign bodies.

6 Claims, 7 Drawing Figures PATENTEBAPR 30 m4 saw 2 [IF 4 1 OUTBO MOTOR HAVING A WATER .IET IMPELLOR UNIT BACKGROUND OF THE INVENTION The present invention relates to an outboard motor for boats and particularly to an outboard motor having a water jet impellor unit including a propeller driven by an internal combustion engine, which draws in water through an inlet duct which, in use of the motor, is submerged and expels it at high speed from an outlet duct, which may also be submerged, thereby creating the thrust for propulsion. Y

OBJECTS OF THE INVENTION One object of this invention is to provide an outboard motor of this type in which the axis of the propeller shaft coincides with the axis of the output shaft of the engine to avoid the necessity for universal joints and/or gears for compensating any angles between the axis of the output shaft of the engine and the axis of the propeller shaft.

Another object of this invention is to provide an outboard motor in which the coinciding axes of the engine and of the propeller shaft are arranged so as to allow the propeller shaft to be directly connected to the output shaft of the engine and yet be inclined to such an extent that the vertical and longitudinal dimensions of the motor are both minimised.

A further object of this invention is to provide an outboard motor which meets the above objects and includes means for connecting it to a boat adapted and arranged so as to substantially eliminate the transmission of any vibrations produced by the reciprocating or rotating parts of the internal combustion engine.

Yet another object of this invention is to provide an outboard motor in which the transmission bearings do not require lubrication.

Yet a further object of the invention is to provide an outboard motor with'a water cooled internal combustion engine having filtration means for the .coolant water which are adapted so as to allow the easy removal of foreign bodies and of any impurities which may get into the system.

Still another object of this invention is to provide an outboard motor of the type described, with an external protective casing which is formed as a unitary structure and in which the means for connecting the motor to the transom of a boat are arranged so as to avoid the direct transmission of vibrations from the engine.

SUMMARY OF THE INVENTION According to the present invention an outboard motor of the type having a water jet impellor unit comprises an engine having an output shaft, water propelling means, a propeller shaft, first coupling means connecting a first end of said propeller shaft to said water propelling means and second coupling means connecting the second end of said propeller shaft to said output shaft for driving said water propelling means, said propeller shaft being inclined, means, said propeller shaft being inclined, when the motor is in a normal orientation, at an angle to the vertical, and aligned with said output shaft of said engine, said second coupling means including means for resisting the axial thrust on said propeller shaft by said water propelling means, bearing means for bearing said second end of said propeller shaft, said bearing means being cooled by water being drawn therethrough by the action of said water propelling means, a shell for supporting said engine and said water propelling means, means for mounting said shell to the transom of a boat, resilient suspension means supporting said engine and said water propelling means on said shell, conduit means for passing cooling water to said engine from said water propelling means, and filter means in said conduit means.

Further objects and advantages of this invention will become apparent during the course of the following detailed description with reference to the accompanying drawings, which is provided purely by way of nonrestrictive example.

BRIEF DESCRIPTION OF THE DRAWINGS -means for mounting the motor casing to the transom of a .boat; and

FIG. 7 is a section taken on the line VII-VII of FIG. 6.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS In the drawings there is shown the combustion engine 1 which drives a propeller 3, which is housed in a duct 4, by means of a propeller shaft 2. The propeller shaft 2 is inclined and forms an angle of at least 10 with the vertical. The output shaft of the engine 1 is aligned with the propeller shaft 2 so that the whole motor is correspondingly inclined. In other embodiments of the invention a different inclination of the propeller shaft may be used and it has been found that an inclination of up to 45 to the vertical can be used with advantage.

The propeller 3 draws in water through an inlet duct and propels it through an elbow chamber to a diffuser duct 6 from which the water emerges at high speed via a nozzle 7 thereby forming a cylindrical jet of water the kinetic energy of which develops the necessary thrust for propulsion.

The engine 1 carries a plate 8, with a support 9 for the duct 4 and the outlet nozzle 7 on which are mounted steering and reversing means 14 which form the subject of a copending application for a patent by the same applicant. The engine 1 with the plate 8, the support 9 and the duct 4 form a propulsion unit which is resiliently suspended in a shell 10 rigidly fixed to the transom SP of the craft. The suspension connection of the propulsion unit to the shell 10 is formed by resilient blocks and bushes which prevent the transmission of vibrations. These bushes and blocks are arranged as illustrated in the drawings. A bolt 11 connects the front of the plate 8 to the shell 10 with the interposition of a resilient bush 11a and a couple of blocks 12a, 12b support the rear of the engine 1 on the shell 10. The bolt 11 and the blocks 12a, 12b have convergent axes which meet at a point A. A pair of bolts 13 having bushes 13a, 13b having axes converging at a point B connect the duct 4 to a part of the shell 10. The centre of gravity C of the propulsion unit lies on the line passing through the points A and B.

This disposition of the resilient suspension elements allows the absorption of the vibrations of the propulsion unit but holds the unit in place in the shell 10. The shell is obtained completely by casting and to facilitate its manufacture it is, as will be seen from the drawings, substantially devoid of undercut parts. This simplification of the shape of the shell is also assisted by the fact that the means for mounting it to the transon SP are independent of the shell itself. The mounting means comprise two brackets joined to the shell by pivots 16 (FIG. 7) which allow the brackets to rotate through a limited angle. An abutment 17 transmits the forces induced by tightening respective joining screws 18, one to each bracket, to the shell 10 (FIG. 6). One of the pivots 16 is longer than the other and projects from the bracket 15 to. form a support 16a for the accelerator control lever 19 and the reversing control lever 20 respectively. The brackets 15 are also connected together by a tubular element 21 which, in addition to making the arrangement rigid, acts as a handle for carrying the motor.

FIG. 3 illustrates in detail the connection of the output shaft 22 of the engine 1 to the propeller shaft 2. The end of the output shaft 22 has a splined spigot engaging in a splined sleeve 23 having a flange 23a carrying a ring of hard material which acts as a rolling track for a thrust roller bearing 24. The sleeve 23 is threaded internally on the lower part to receive a correspondently threaded end of the propeller shaft 2. A ring 25 forms the second rolling track for the roller bearing 24. This ring 25 also acts as a centralising element among the various elements of the coupling, and provides support for one or more sealing rings (not shown) which act to prevent the escape of lubricant from the internal chamber 26 of the coupling.

F IG. 4 illustrates the other end of the propeller shaft 2 to which is connected the propeller 3. The connection is advantageously formed by a tapered part of the shaft with the interposition of a sleeve 27 held in place by a nut 28. The outer surface of the sleeve 27 is freely rotatable inside a rubber bearing 29 with longitudinal ridges 30, the bearing 29 being carried by a centre body located by struts 4a. The centre body has an opening 31 in the lower end which allows water to enter into the inner part of the bearing. On the lower face of the propeller 3 there are formed radial grooves 32 which, because of the rotation .of the propeller, create a reduction in pressure in an annular chamber 33 which draws the water through the openings 31 and along the longitudinal grooves of the bearing 29 to cool it. Cooling of the engine on the other hand, is obtained by drawing part of the water under pressure from the elbow chamber 5 of the duct 4, and conveying it coaxially to the propeller shaft 2 through an annular conduit 34 and through a filter 35. The filter 35, which is illustrated in detail in FIG. 5, is shaped so as to allow an undeviated flow of cooling water. The filter is formed by a small perforated plate 36 having a Z-shaped profile. The water, travelling in the direction indicated by the arrow C passes through this small plate leaving behind on its inclined face D any foreign bodies or impurities and these, due to the vibration of the engine, are shaken onto the lower face E of the said plate 36 and are held there by a flange F. The plate 36 is held in position by a stud 37 on which engages a nut 38 which is tightened onto lid 39 which holds the plate 36. By removing this lid it is possible to lift out the plate 36 perpendicularly to the axis of the conduit and thus easily remove it together with the impurities and. foreign bodies held thereby. I

Having now particularly described this invention it will be apparent that one skilled in the art may make many modifications and changes to the embodiment described merely by way of example, without departing from the spirit and scope of the invention. 4

We claim:

1. An outboard motor of the type having a water jet impellor unit, comprising:

an engine having an output shaft,

water propelling means,

a propeller shaft,

first coupling means connecting a first end of said propeller shaft to said water propelling means and second coupling means connecting the second end of said propeller shaft to said output shaft for driving said water propelling means, said propeller shaft being inclined, when the motor is in a normal orientation, at an angle to the vertical, and aligned with said output shaft of said engine, said second coupling means including means for resisting the axial thrust on said propeller shaft by said water propelling means,

bearing means for bearing said first end of said propeller shaft, said bearing means being cooled by water being drawn-therethrough by the action of said water propelling means,

a shell for supporting said engine and said water propelling means,

means for mounting said shell to the transom of a boat,

resilient suspension means supporting said engine and said water propelling means on said shell, conduit means for passing cooling water to said engine, from said water propelling means, and filter means in said conduit means.

2. The outboard motor of claim 1 wherein said means for resisting the axial thrust on said propeller shaft by said water propelling means is a thrust bearing having two annular tracks between which roll a plurality of rolling elements, a first one of said tracks being formed on a splined sleeve connected to said output shaft of said engine and a second one of said tracks being formed on a centralisation ring which centrally locates said splined sleeve.

3. The outboard motor of claim 1, wherein said bearing means for said first end of said propeller shaft include a rubber bush having a plurality of axial grooves, and

said water propelling means includes a propeller adjacent said bearing means and having a plurality of radial grooves on the surface thereof facing said bearing means which act to create a low pressure region, when said propeller is turning, to draw water through said bearing means.

4. The outboard motor of claim 1 wherein said resilient suspension means between said support shell and said engine comprise three resilient elements the axes of which converge at a first point, and the resilient suspension means between said support shell and said water propelling means comprise two resilient bushes mounted on bolts the axes of which converge at a second point, said axes being arranged such that the centre of gravity of the propulsion unit comprising said engine and said water propelling means lies on the line joining said first and second points.

5. The outboard motor of claim 1 wherein said filter in said conduit means for passing cooling water to said engine from said water propelling means comprises a perforated plate the longitudinal section of which is Z- shaped, said filter being located in a housing in said conduit which opens to allow said filter plate to be removed in a direction perpendicular to said conduit,

brackets and forms a handle for said motor.

Dedication 3,807,344.Dante Giacosa, Turin, Italy, OUTBOARD MOTOR HAVING A WATER JET IMPELLOR UNIT. Patent dated Apr. 30, 1974. Dedication filed Jan. 13, 1981, by the assignee, FIATS. p.A. Hereby dedicates to the Public the term of the patent subsequent to December 24, 1980. [Official Gazette May 12, 1981.] 

1. An outboard motor of the type having a water jet impellor unit, comprising: an engine having an outpuT shaft, water propelling means, a propeller shaft, first coupling means connecting a first end of said propeller shaft to said water propelling means and second coupling means connecting the second end of said propeller shaft to said output shaft for driving said water propelling means, said propeller shaft being inclined, when the motor is in a normal orientation, at an angle to the vertical, and aligned with said output shaft of said engine, said second coupling means including means for resisting the axial thrust on said propeller shaft by said water propelling means, bearing means for bearing said first end of said propeller shaft, said bearing means being cooled by water being drawn therethrough by the action of said water propelling means, a shell for supporting said engine and said water propelling means, means for mounting said shell to the transom of a boat, resilient suspension means supporting said engine and said water propelling means on said shell, conduit means for passing cooling water to said engine, from said water propelling means, and filter means in said conduit means.
 2. The outboard motor of claim 1 wherein said means for resisting the axial thrust on said propeller shaft by said water propelling means is a thrust bearing having two annular tracks between which roll a plurality of rolling elements, a first one of said tracks being formed on a splined sleeve connected to said output shaft of said engine and a second one of said tracks being formed on a centralisation ring which centrally locates said splined sleeve.
 3. The outboard motor of claim 1, wherein said bearing means for said first end of said propeller shaft include a rubber bush having a plurality of axial grooves, and said water propelling means includes a propeller adjacent said bearing means and having a plurality of radial grooves on the surface thereof facing said bearing means which act to create a low pressure region, when said propeller is turning, to draw water through said bearing means.
 4. The outboard motor of claim 1 wherein said resilient suspension means between said support shell and said engine comprise three resilient elements the axes of which converge at a first point, and the resilient suspension means between said support shell and said water propelling means comprise two resilient bushes mounted on bolts the axes of which converge at a second point, said axes being arranged such that the centre of gravity of the propulsion unit comprising said engine and said water propelling means lies on the line joining said first and second points.
 5. The outboard motor of claim 1 wherein said filter in said conduit means for passing cooling water to said engine from said water propelling means comprises a perforated plate the longitudinal section of which is Z-shaped, said filter being located in a housing in said conduit which opens to allow said filter plate to be removed in a direction perpendicular to said conduit, carrying any impurities and/or foreign bodies collected thereby.
 6. The outboard motor of claim 1 wherein said means for mounting said shell to the transom of a boat comprises a pair of brackets pivotally mounted on said shell, the pivot pin of one of said brackets having an axial extension forming a pivotal support for the control levers of the motor, the two brackets being connected together by a reinforcing element which lies substantially parallel to the axes of said pivots of said brackets and forms a handle for said motor. 